Key Takeaways:

The procedure comes with extra risks and costs, with uncertain long-term outcomes.

When a blood clot develops in a vein deep in the body, doctors traditionally use blood thinners to keep the clot from getting bigger and give it time to dissolve on its own, according to the National Heart, Lung, and Blood Institute. But there is a newer and more aggressive approach to this condition known as deep vein thrombosis (DVT).

The new method calls for injecting clot-busting drugs directly into the clot to dissolve it, or using a mechanical device to break it up, according to the Radiological Society of North America.

“This is a fascinating and controversial area of medicine, whether to perform catheter-directed thrombolysis (CDT) for deep vein thrombosis,” says Natalie Evans, MD, a cardiologist with the Cleveland Clinic in Ohio. But while the new method is increasingly popular, it comes with added risks and extra costs.

Risks and Benefits of Catheter-Directed Thrombolysis

Researchers set out assess the risks and benefits of catheter-directed thrombolysis in a study that analyzed data on more than 90,000 people who were hospitalized with DVT over a five-year span. About 4 percent of them were treated with CDT. The findings were published in JAMA Internal Medicine in July 2014.

They found that people who had clot-busting medication delivered directly into a clot with a catheter were no more likely to die while hospitalized than those who were treated with standard anticoagulant therapy (blood thinners). However, clot busting via catheter carried a higher risk for bleeding problems, such as hemorrhaging in the brain, and required more blood transfusions.

Use of catheter-directed thrombolysis for deep vein thrombosis has doubled in recent years.

Another risk uncovered was that more people in the study group treated with CDT developed pulmonary embolism: 18 percent versus 11 percent of those treated only with blood thinners. According to the National Heart, Lung, and Blood Institute, pulmonary embolism occurs when a clot breaks loose, travels through the bloodstream, and lodges in a lung artery — and can be life threatening.

The newer method costs about three times as much as blood thinning therapy. On average, CDT was $85,094 compared with $28,164 for anticoagulant treatment. And clot busting required a longer hospital stay, according to the study.

“Now we know what the safety profile of CDT treatment is,” says study author and interventional cardiologist Riyaz Bashir, MD, an associate professor of medicine at the Temple University School of Medicine in Philadelphia. That's important in part because the mechanical clot-busting procedure is slowly gaining in popularity, he says.

The study reported that the use of CDT more than doubled between 2005 and 2010, increasing from use in about 2 percent of patients with DVT to 6 percent.

However, Dr. Bashir says it's still not always offered as a treatment option to patients, even those who he says would have the lowest risk profile: younger people with DVT who are otherwise generally healthy.

“So now when a patient comes to a physician and has a blood clot in his or her legs, the physician should inform the patient what the options are. Let the patient participate in shared decision making," he says. "The risks can be individualized for various patients.”

Continuing Questions About Catheter-Directed Thrombolysis

Whether the results of Bashir's study apply to all people with deep vein thrombosis remains unclear. The researchers acknowledged that caveat in their report. They note that the findings reflected only what occurred while people were hospitalized. It didn't include information on outcomes once people were discharged — a factor for future study.

Use of catheter-directed thrombolysis for deep vein thrombosis has doubled in recent years.

As Dr. Evans notes: “The reason we want to do CDT is to prevent long-term complications. Some patients with DVT in the leg will develop post-thrombotic syndrome, which includes leg pain, swelling, and even ulcers. The question is, does CDT prevent this? We actually don’t know the answer yet.”

According to research published in the American Heart Journal in April 2013, post-thrombotic syndrome occurs in about 40 percent of people with DVT within two years after a deep vein thrombosis in the lower extremities.

In fact, Bashir's study did not address longer-term outcomes for either CDT or anticoagulant therapy, but that's at the heart of the American Heart Journal study, called the ATTRACT trial, which is still recruiting participants. This new study will compare anticoagulant therapy, CDT, and a CDT/anticoagulant combination. It will also include data on participants once they leave the hospital. They'll be followed for two years after treatment to better assess the impact of the three treatment options on post-thrombotic syndrome, people's quality of life, and more.